- Volume 74, Issue 4, 2024

A Gram-stain-negative, motile, aerobic, non-spore-forming coccus, designated strain CR14T, was isolated from crustose coralline algae. Cells grew at 20–30 °C (optimum, 25 °C), at pH 6–9 (optimum, pH 7.6) and with NaCl concentrations of 0.5–9 % (w/v; optimum, 2–4 %). Global alignment based on 16S rRNA gene sequences indicated strain CR14T is closest to Ruficoccus amylovorans JCM 31066T with an identity of 92 %. The average nucleotide identity and average amino acid identity values between CR14T and R. amylovorans JCM 31066T were 68.4 and 59.9 %, respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CR14T forms an independent branch within the family Cerasicoccaeae, which was consistent with the phylogenomic results. The sole isoprenoid quinone was MK-7. The major fatty acids were C14 : 0, C18 : 1 ω9c, C19 : 0 cyc 9,10 DMA, C16 : 0, and C18 : 2 ω6c. The major cellular polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and two unidentified lipids. The genome DNA G+C content was 48.7 mol%. Based on morphological, physiological and chemotaxonomic characteristics, strain CR14T is suggested to represent a novel species in a new genus, for which the name Rubellicoccus peritrichatus gen. nov., sp. nov. is proposed. The type strain is CR14T (=MCCC 1K03845T=KCTC 72139T).

By investigating wet and dry age-related ripening of beef, Pseudomonas strains V3/3/4/13T and V3/K/3/5T were isolated. Strain V3/3/4/13T exhibited more than 99 % 16S rRNA gene-based similarity to Pseudomonas fragi and other members of this group, while isolate V3/K/3/5T was very close to Pseudomonas veronii and a number of relatives within the Pseudomonas fluorescens group. Additional comparisons of complete rpoB sequences and draft genomes allowed us to place isolate V3/3/4/13T close to Pseudomonas deceptionensis DSM 26521T. In the case of V3/K/3/5T the closest relative was P. veronii DSM 11331T. Average nucleotide identity (ANIb) and digital DNA–DNA hybridization (dDDH) values calculated from the draft genomes of V3/3/4/13T and P. deceptionensis DSM 26521T were 88.5 and 39.8 %, respectively. For V3/K/3/5T and its closest relative P. veronii DSM 11331T, the ANIb value was 95.1 % and the dDDH value was 60.7 %. The DNA G+C contents of V3/3/4/13T and V3/K/3/5T were 57.4 and 60.8 mol%, respectively. Predominant fatty acids were C16 : 0, C18 : 1 ω7c, C17 : 0 cyclo and summed feature C16 : 1 ω7ct/C15 : 0 iso 2OH. The main respiratory quinones were Q9, with minor proportions of Q8 and, in the case of V3/K/3/5T, additional Q10. The main polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and, in the case of V3/K/3/5T, additional phosphatidylcholine. Based on the combined data, isolates V3/3/4/13T and V3/K/3/5T should be considered as representatives of two novel Pseudomonas species. The type strain of the newly proposed Pseudomonas kulmbachensis sp. nov. is V3/3/4/13T (=DSM 113654T=LMG 32520T), a second strain belonging to the same species is FLM 004-28 (=DSM 113604=LMG 32521); the type strain for the newly proposed Pseudomonas paraveronii sp. nov. is V3/K/3/5T (=DSM 113573T=LMG 32518T) with a second isolate FLM 11 (=DSM 113572=LMG 32519).

A novel moderately halophilic, Gram-stain-negative and facultatively anaerobic bacterium, designated as strain TBZ242T, was isolated from water of Urmia Lake in the Azerbaijan region of Iran. The cells were found to be rod-shaped and motile by a single polar flagellum, producing circular and yellowish colonies. The strain could grow in the presence of 0.5–10 % (w/v) NaCl (optimum, 2.5–5 %). The temperature and pH ranges for growth were 15–45 °C (optimum 30 °C) and pH 7.0–11.0 (optimum pH 8.0) on marine agar. The 16S rRNA gene sequence analysis revealed that strain TBZ242T belonged to the genus Marinobacter, showing the highest similarities to Marinobacter algicola DG893T (98.8 %), Marinobacter vulgaris F01T (98.8 %), Marinobacter salarius R9SW1T (98.5 %), Marinobacter panjinensis PJ-16T (98.4 %), Marinobacter orientalis W62T (98.0 %) and Marinobacter denitrificans JB2H27T (98.0 %). The 16S rRNA and core-genome phylogenetic trees showed that strain TBZ242T formed a distinct branch, closely related to a subclade accommodating M. vulgaris, M. orientalis, M. panjinensis, M. denitrificans, M. algicola, M. salarius and M. iranensis, within the genus Marinobacter. Average nucleotide identity and digital DNA–DNA hybridization values between strain TBZ242T and the type strains of the related species of Marinobacter were ≤85.0 and 28.6 %, respectively, confirming that strain TBZ242T represents a distinct species. The major cellular fatty acids of strain TBZ242T were C16 : 0 and C16 : 1  ω7c/C16 : 1 ω6c and the quinone was ubiquinone Q-9. The genomic DNA G+C content of strain TBZ242T is 57.2 mol%. Based on phenotypic, chemotaxonomic and genomic data, strain TBZ242T represents a novel species within the genus Marinobacter, for which the name Marinobacter azerbaijanicus sp. nov. is proposed. The type strain is TBZ242T (= CECT 30649T = IBRC-M 11466T). Genomic fragment recruitment analysis showed that this species prefers aquatic saline environments with intermediate salinities, being detected on metagenomic databases of Lake Meyghan (Iran) with 5 and 18 % salinity, respectively.

A novel Gram-stain-negative and facultatively anaerobic bacterium, designated A6E488T, was isolated from intertidal sediment collected from Xiaoshi Island, Weihai, PR China (122° 1′ E 37° 31′ N). Cells of strain A6E488T were rod-shaped with widths of 0.3–0.4 µm and lengths of 1.1–1.8 µm. The optimal growth conditions were determined to be in 1 % (w/v) NaCl, at 37 °C, and at pH 7.0. The predominant fatty acids (≥10 %) were C19 : 0 cyclo ω8c (59.7 %) and summed feature 8 (13.8 %, C18 : 1 ω7c and/or C18 : 1 ω6c). The sole isoprenoid quinone was Q-10. Oxidase activity was negative but catalase activity was positive. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid, one unidentified aminolipid, one unidentified glycolipid, and one unidentified lipid. Based on phylogenetic analysis of 16S rRNA gene sequences, strain A6E488T showed the highest sequence similarity to Microbaculum marinum MCCC 1K03192T (97.6 %). The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between strain A6E488T and M. marinum MCCC 1K03192T did not exceed 78 and 22 %, respectively. These values are below the recommended thresholds of 95 % (ANI) and 70 % (dDDH) for prokaryotic species delineation. On the basis of gene annotation, it was observed that strain A6E488T possesses the capability for thiosulphate oxidation, suggesting that this strain might be important in the sulphur cycle. Based on the results of phenotypic, genotypic, and chemical characterization, strain A6E488T is considered to represent a novel species of the genus Microbaculum, for which the name Microbaculum marinisediminis sp. nov. is proposed. The type strain is A6E488T (=KCTC 92197T=MCCC 1H00516T).

A Gram-stain-negative, aerobic, oxidase-positive, weakly catalase-positive, motile by means of a single polar flagellum, rod-shaped bacterium designated as strain S2-9T was isolated from sediment sampled in Wiyang pond, Republic of Korea. Growth of this strain was observed at 10–40 °C (optimum, 35 °C) and pH 5.5–9.5 (optimum, pH 7.0–8.0) and in the presence of 0–0.5 % NaCl in Reasoner's 2A broth. The major fatty acids (>10 %) of strain S2-9T were C16 : 0 and summed feature 3 (comprising a mixture of C16 : 1  ω7c and/or C16 : 1  ω6c). Ubiquinone-8 was detected as the respiratory quinone. The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. Strain S2-9T showed the highest 16S rRNA gene sequence similarity to Paucibacter oligotrophus CHU3T (98.7 %), followed by ‘Paucibacter aquatile’ CR182 (98.4 %), all type strains of Pelomonas species (98.1–98.3 %), Mitsuaria chitosanitabida NBRC 102408T (97.9 %), Kinneretia asaccharophila KIN192T (97.8 %), Mitsuaria chitinivorans HWN-4T (97.4 %), and Paucibacter toxinivorans 2C20T (97.4 %). Phylogenetic trees based on the 16S rRNA gene and whole-genome sequences showed that strain S2-9T formed a tight phylogenetic lineage with Paucibacter species (CHU3T, CR182, and 2C20T). Average nucleotide identity and digital DNA–DNA hybridization values between strain S2-9T and Paucibacter strains were 76.6–79.3% and 19.5–21.5 %, respectively. The genomic DNA G+C content of strain S2-9T was 68.3 mol%. Notably, genes responsible for both sulphur oxidation and reduction and denitrification were found in the genome of strain S2-9T, suggesting that strain S2-9T is involved in the nitrogen and sulphur cycles in pond ecosystems. Based on the polyphasic taxonomic results, strain S2-9T represents a novel species of the genus Paucibacter, for which the name Paucibacter sediminis sp. nov. is proposed. The type strain is S2-9T (= KACC 22267T= JCM 34541T).

An aerobic methanotroph was isolated from a secondary sedimentation tank of a wastewater treatment plant and designated strain OY6T. Cells of OY6T were Gram-stain-negative, pink-pigmented, motile rods and contained an intracytoplasmic membrane structure typical of type I methanotrophs. OY6T could grow at a pH range of 4.5–7.5 (optimum pH 6.5) and at temperatures ranging from 20 °C to 37 °C (optimum 30 °C). The major cellular fatty acids were C14 : 0, C16 : 1ω7c/C16 : 1ω6c and C16 : 1ω5c; the predominant respiratory quinone was MQ-8. The genome size was 5.41 Mbp with a DNA G+C content of 51.7 mol%. OY6T represents a member of the family Methylococcaceae of the class Gammaproteobacteria and displayed 95.74–99.64 % 16S rRNA gene sequence similarity to the type strains of species of the genus Methylomonas. Whole-genome comparisons based on average nucleotide identity (ANI) and digital DNA–DNA hybridisation (dDDH) confirmed that OY6T should be classified as representing a novel species. The most closely related type strain was Methylomonas fluvii EbBT, with 16S rRNA gene sequence similarity, ANI by blast (ANIb), ANI by MUMmer (ANIm) and dDDH values of 99.64, 90.46, 91.92 and 44.5 %, respectively. OY6T possessed genes encoding both the particulate methane monooxygenase enzyme and the soluble methane monooxygenase enzyme. It grew only on methane or methanol as carbon sources. On the basis of phenotypic, genetic and phylogenetic data, strain OY6T represents a novel species within the genus Methylomonas for which the name Methylomonas defluvii sp. nov. is proposed, with strain OY6T (=GDMCC 1.4114T=KCTC 8159T=LMG 33371T) as the type strain.

Two novel Gram-stain-negative, aerobic, non-motile and rod-shaped bacteria, designated as WL0004T and XHP0148T, were isolated from seawater samples collected from the coastal areas of Nantong and Lianyungang, PR China, respectively. Both strains were found to grow at 10–42 °C (optimum, 37 °C) and with 2.0–5.0 % (w/v) NaCl (optimum, 3.0 %). Strain WL0004T grew at pH 6.0–9.0 (optimum, pH 7.0–8.0), while XHP0148T grew at pH 6.0–10.0 (optimum, pH 7.0–8.0). The major cellular fatty acids (>10 %) of both strains included summed feature 8 (C18 : 1  ω6c and/or C18 : 1  ω7c). In addition, strain WL0004T contained 11-methyl C18 : 1  ω7c and strain XHP0148T contained C12 : 0 3-OH. The respiratory quinone of both strains was ubiquinone-10. The G+C content of genomic DNA of strains WL0004T and XHP0148T were 62.5 and 63.0 mol%, respectively. Strains WL0004T and XHP0148T showed the highest 16S rRNA gene sequence similarity to Ruegeria pomeroyi DSS-3T (99.4 and 99.0 %, respectively), and the 16S rRNA gene-based phylogenetic analysis indicated that the two strains were closely related to members of the genus Ruegeria. The average nucleotide identity and digital DNA–DNA hybridization values among the two strains and type strains of the genus Ruegeria were all below 95 and 70 %, respectively, and the phylogenetic tree reconstructed from the bac120 gene set indicated that the two strains are distinct from each other and the members of the genus Ruegeria. Based on this phenotypic and genotypic characterization, strains WL0004T (=MCCC 1K07523T=JCM 35565T=GDMCC 1.3083T) and XHP0148T (=MCCC 1K07543T=JCM 35569T=GDMCC 1.3089T) should be recognized as representing two novel species of the genus Ruegeria and the names Ruegeria marisflavi sp. nov. and Ruegeria aquimaris sp. nov. are proposed, respectively.

Phytopathogenic bacteria (MAFF 302110T and MAFF 302107) were isolated from lesions on Japanese angelica trees affected by bacterial soft rot in Yamanashi Prefecture, Japan. The strains were Gram-reaction-negative, facultatively anaerobic, motile with peritrichous flagella, rod-shaped, and non-spore-forming. The genomic DNA G+C content was 51.1 mol % and the predominant cellular fatty acids included summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), C16 : 0, summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), summed feature 2 (comprising any combination of C12 : 0 aldehyde, an unknown fatty acid with an equivalent chain length of 10.928, C16 : 1 iso I, and C14 : 0 3OH), and C12 : 0. Phylogenetic analyses based on 16S rRNA and gyrB gene sequences, along with phylogenomic analysis utilizing whole-genome sequences, consistently placed these strains within the genus Pectobacterium. However, their phylogenetic positions did not align with any known species within the genus. Comparative studies involving average nucleotide identity and digital DNA–DNA hybridization with the closely related species indicated values below the thresholds employed for the prokaryotic species delineation (95–96 % and 70 %, respectively), with the highest values observed for Pectobacterium polonicum DPMP315T (92.10 and 47.1 %, respectively). Phenotypic characteristics, cellular fatty acid composition, and a repertoire of secretion systems could differentiate the strains from their closest relatives. The phenotypic, chemotaxonomic, and genotypic data obtained in this study show that MAFF 302110T/MAFF 302107 represent a novel species of the genus Pectobacterium, for which we propose the name Pectobacterium araliae sp. nov., designating MAFF 302110T (=ICMP 25161T) as the type strain.

A Gram-stain-negative, aerobic, rod-shaped and halotolerant bacterium, designated as strain ASW11-75T, was isolated from intertidal sediments in Qingdao, PR China, and identified using a polyphasic taxonomic approach. Growth of strain ASW11-75T occurred at 10–45 °C (optimum, 37 °C), pH 6.5–9.0 (optimum, pH 8.0) and 0.5–18.0 % NaCl concentrations (optimum, 2.5 %). Phylogenetic analyses based on 16S rRNA gene sequences and 1179 single-copy orthologous clusters indicated that strain ASW11-75T is affiliated with the genus Marinobacter. Strain ASW11-75T showed highest 16S rRNA gene sequence similarity to ‘Marinobacter arenosus’ CAU 1620T (98.5 %). The digital DNA–DNA hybridization and average nucleotide identity values between strain ASW11-75T and its closely related strains (Marinobacter salarius R9SW1T, Marinobacter similis A3d10T, ‘Marinobacter arenosus’ CAU 1620T, Marinobacter sediminum R65T, Marinobacter salinus Hb8T, Marinobacter alexandrii LZ-8T and Marinobacter nauticus ATCC 49840T) were 19.8–24.5 % and 76.6–80.7 %, respectively. The predominant cellular fatty acids were C16 : 0, C18 : 1  ω9c and C16 : 0 N alcohol. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified aminophospholipid and two unidentified lipids. The major isoprenoid quinone was ubiquinone-9. The genomic DNA G+C content was 62.2 mol%. Based on genomic and gene function analysis, strain ASW11-75T had lower protein isoelectric points with higher ratios of acidic residues to basic residues and possessed genes related to ion transport and organic osmoprotectant uptake, implying its potential tolerance to salt. The results of polyphasic characterization indicated strain ASW11-75T represents a novel Marinobacter species, for which the name Marinobacter qingdaonensis sp. nov. with the type strain ASW11-75T is proposed. The type strain is ASW11-75T (=KCTC 82497T=MCCC 1K05587T).

The alphaproteobacterial order Hyphomicrobiales consists of 38 families comprising at least 152 validly published genera as of January 2024. The order Hyphomicrobiales was first described in 1957 and underwent important revisions in 2020. However, we show that several inconsistencies in the taxonomy of this order remain and we argue that there is a need for a consistent framework for defining families within the order. We propose a common genome-based framework for defining families within the order Hyphomicrobiales, suggesting that families represent monophyletic groups in core-genome phylogenies that share pairwise average amino acid identity values above ~75 % when calculated from a core set of 59 proteins. Applying this framework, we propose the formation of four new families and to reassign the genera Salaquimonas, Rhodoblastus, and Rhodoligotrophos into Salaquimonadaceae fam. nov., Rhodoblastaceae fam. nov., and Rhodoligotrophaceae fam. nov., respectively, and the genera Albibacter, Chenggangzhangella, Hansschlegelia, and Methylopila into Methylopilaceae fam. nov. We further propose to unify the families Bartonellaceae, Brucellaceae, Phyllobacteriaceae, and Notoacmeibacteraceae as Bartonellaceae; the families Segnochrobactraceae and Pseudoxanthobacteraceae as Segnochrobactraceae; the families Lichenihabitantaceae and Lichenibacteriaceae as Lichenihabitantaceae; and the families Breoghaniaceae and Stappiaceae as Stappiaceae. Lastly, we propose to reassign several genera to existing families. Specifically, we propose to reassign the genus Pseudohoeflea to the family Rhizobiaceae; the genera Oricola, Roseitalea, and Oceaniradius to the family Ahrensiaceae; the genus Limoniibacter to the emended family Bartonellaceae; the genus Faunimonas to the family Afifellaceae; and the genus Pseudochelatococcus to the family Chelatococcaceae. Our data also support the recent proposal to reassign the genus Prosthecomicrobium to the family Kaistiaceae.

Two Gram-stain-negative bacterial strains, R39T and R73T, were isolated from the rhizosphere soil of the selenium hyperaccumulator Cardamine hupingshanesis in China. Strain R39T transformed selenite into elemental and volatile selenium, whereas strain R73T transformed both selenate and selenite into elemental selenium. Phylogenetic and phylogenomic analyses indicated that strain R39T belonged to the genus Achromobacter, while strain R73T belonged to the genus Buttiauxella. Strain R39T (genome size, 6.68 Mb; G+C content, 61.6 mol%) showed the closest relationship to Achromobacter marplatensis LMG 26219T and Achromobacter kerstersii LMG 3441T, with average nucleotide identity (ANI) values of 83.6 and 83.4 %, respectively. Strain R73T (genome size, 5.22 Mb; G+C content, 50.3 mol%) was most closely related to Buttiauxella ferragutiae ATCC 51602T with an ANI value of 86.4 %. Furthermore, strain A111 from the GenBank database was found to cluster with strain R73T within the genus Buttiauxella through phylogenomic analyses. The ANI and digital DNA–DNA hybridization values between strains R73T and A111 were 97.5 and 80.0% respectively, indicating that they belong to the same species. Phenotypic characteristics also differentiated strain R39T and strain R73T from their closely related species. Based on the polyphasic analyses, strain R39T and strain R73T represent novel species of the genera Achromobacter and Buttiauxella, respectively, for which the names Achromobacter seleniivolatilans sp. nov. (type strain R39T=GDMCC 1.3843T=JCM 36009T) and Buttiauxella selenatireducens sp. nov. (type strain R73T=GDMCC 1.3636T=JCM 35850T) are proposed.

A novel Gram-stain-negative, yellow-pigmented, short rod-shaped bacterial strain, HBC34T, was isolated from a freshwater sample collected from Daechung Reservoir, Republic of Korea. The results of 16S rRNA gene sequence analysis indicated that HBC34T was affiliated with the genus Sphingobium and shared the highest sequence similarity to the type strains of Sphingobium vermicomposti (98.01 %), Sphingobium psychrophilum (97.87 %) and Sphingobium rhizovicinum (97.59 %). The average nucleotide identity (ANI) and digital DNA–DNA hybridisation (dDDH) values between HBC34T and species of the genus Sphingobium with validly published names were below 84.01 and 28.1 %, respectively. These values were lower than the accepted species-delineation thresholds, supporting its recognition as representing a novel species of the genus Sphingobium. The major fatty acids (>10 % of the total fatty acids) were identified as summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The main polar lipids were phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, two phospholipids and two unidentified polar lipids. The respiratory quinone was Q-10. The genomic DNA G+C content of HBC34T was 64.04 %. The polyphasic evidence supports the classification of HBC34T as the type strain of a novel species of the genus Sphingobium, for which the name Sphingobium cyanobacteriorum sp. nov is proposed. The type strain is HBC34T (= KCTC 8002T= LMG 33140T).

A Gram-stain-negative, non-motile, and slightly halophilic alphaproteobacterium, designated strain EGI FJ00035T, was isolated from enrichment sediment samples of a saline lake in Xinjiang Uygur Autonomous Region, PR China. The taxonomic position of the isolate was determined using the polyphasic taxonomic and phylogenomic analyses. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain EGI FJ00035T formed a distinct clade with ‘Chelativorans alearense’ UJN715 and ‘Chelativorans xinjiangense’ lm93 with sequence similarities of 98.44 and 98.22 %, respectively, while sharing less than 96.7 % with other valid type strains. The novel isolate could be distinguished from other species of the genus Chelativorans by its distinct phenotypic, physiological, and genotypic characteristics. Optimal growth of strain EGI FJ00035T occurred on marine agar 2216 at pH 7.0 and 30 °C. The major respiratory quinone was Q-10, while the major fatty acids (>5 %) were C19 : 0 cyclo ω8c, summed feature 8 (C17 : 1 ω6c and/or C17 : 1 ω7c), C16 : 0, C18 : 0, and iso-C17 : 0. The detected polar lipids included diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, unidentified aminophospholipids, unidentified glycolipids, and an unidentified lipid. Based on its genome sequence, the G+C content of strain EGI FJ00035T was 63.2 mol%. The average nucleotide identity, average amino acid identity, and digital DNA–DNA hybridization values of strain EGI FJ00035T against related members of the genus Chelativorans were below the thresholds for delineation of a novel species. According our polyphasic taxonomic data, strain EGI FJ00035T represents a new species of the genus Chelativorans, for which the name Chelativorans salis sp. nov. is proposed. The type strain of the proposed novel isolate is EGI FJ00035T (=KCTC 92251T=CGMCC 1.19480T).

A Gram-stain-negative bacterium, designated XZ-24T, was isolated from sediment of a river in Mianyang city, Sichuan province, PR China. Cells (1.0–2.0 µm long and 0.4–0.5 µm in width) were strictly aerobic, non-spore-forming, rod shaped, prosthecate and motile by means of a polar flagellum. Growth occurred at 10–37 °C (optimum, 30 °C), at pH 5.0–9.0 (optimum pH 7.0) and with 0–3.0 % (w/v) NaCl (optimum 1.0 % NaCl). The results of phylogenetic analysis based on genomes and 16S rRNA gene sequences indicated that XZ-24T formed a distinct phyletic branch within the family Caulobacteraceae and was most closely related to members of the genera Brevundimonas, Caulobacter and Phenylobacterium with 95.3–96.5 % 16S rRNA gene sequence similarities. The average amino acid identities (AAI) between XZ-24T and species of the family Caulobacteraceae were 47.0–64.5 %, which were below the genus boundary (70 %). The predominant cellular fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0, C18 : 1ω7c 11-methyl and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), the isoprenoid quinone was Q-10, and the major polar lipids were 1,2-di-O-acyl-3-O-α-d-glucopyranuronosyl glycerol; 1,2-di-O-acyl-3-O-[d-glucopyranosyl-(1→4)-α-d glucopyranuronosyl] glycerol and phosphatidylglycerol. The genome size of XZ-24T was 2.64 Mb with a DNA G+C content of 68.9 %. On the basis of the evidence presented in this study, strain XZ-24T represents a novel species of a novel genus in the family Caulobacteraceae, for which the name Peiella sedimenti gen. nov., sp. nov. (Type strain XZ-24T=CCTCC AB 20 23 094T=KCTC 8038T) is proposed.

A Gram-negative, motile, rod-shaped bacterial strain, CA-0114T, was isolated from the midgut of a western honey bee, Apis mellifera. The isolate exhibited ≤96.43 % 16S rRNA gene sequence identity (1540 bp) to members of the families Enterobacteriaceae and Erwiniaceae. Phylogenetic trees based on genome blast distance phylogeny and concatenated protein sequences encoded by conserved genes atpD, fusA, gyrB, infB, leuS, pyrG and rpoB separated the isolate from other genera forming a distinct lineage in the Enterobacteriaceae. In both trees, the closest relatives were Tenebrionicola larvae YMB-R21T and Tenebrionibacter intestinalis BIT-L3T, which were isolated previously from Tenebrio molitor L., a plastic-eating mealworm. Digital DNA–DNA hybridization, orthologous average nucleotide identity and average amino acid identity values between strain CA-0114T and the closest related members within the Enterobacteriaceae were ≤23.1, 75.45 and 76.04 %, respectively. The complete genome of strain CA-0114T was 4 451669 bp with a G+C content of 52.12 mol%. Notably, the apparent inability of strain CA-0114T to ferment d-glucose, inositol and l-rhamnose in the API 20E system is unique among closely related members of the Enterobacteriaceae. Based on the results obtained through genotypic and phenotypic analysis, we propose that strain CA-0114T represents a novel species and genus within the family Enterobacteriaceae, for which we propose the name Apirhabdus apintestini gen. nov., sp. nov. (type strain CA-0114T=ATCC TSD-396T=DSM 116385T).

Two Gram-negative bacterial strains designated MMS20-SJTN17T and MMS20-SJTR3T were isolated from a grassland soil sample, and taxonomically characterized using a polyphasic approach. The 16S rRNA gene sequence analysis indicates that both strains belong to the genus Paraburkholderia of the class Betaproteobacteria, with strain MMS20-SJTN17T being mostly related to Paraburkholderia sprentiae WSM5005T (96.45 % sequence similarity) and strain MMS20-SJTR3T to Paraburkholderia tuberum STM678T (98.59 % sequence similarity). MMS20-SJTN17T could grow at 15–40 °C (optimum, 25–30 °C) and at pH 6.0–8.0 (optimum, pH 6.0–7.0), whereas MMS20-SJTR3T could grow at 10–40 °C (optimum, 30–37 °C) and at pH 6.0–8.0 (optimum, pH 6.0). Both strains tolerated up to 1 % (w/v) NaCl (optimum, 0 %). The major fatty acids of MMS20-SJTN17T were C16 : 0 and C19 : 0 cyclo ω8c, and those of MMS20-SJTR3T were C17 : 0 cyclo and a summed feature comprising C18 : 1 ω7c and/or C18 : 1 ω6c. The major isoprenoid quinone of both strains was ubiquinone-8 and the diagnostic polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Regarding plant growth promoting potential, both strains were capable of producing indole acetic acid, siderophore and 1-aminocyclopropane-1-carboxylic acid deaminase, and also showed phosphate-solubilizing activity. A genome-based comparison using orthologous average nucleotide identity and digital DNA–DNA hybridization values indicates that strain MMS20-SJTN17T shares highest relatedness with Paraburkholderia monticola JC2948T and MMS20-SJTR3T with Paraburkholderia antibiotica G-4-1-8T, with values clearly below the cutoffs for species distinction. Examination of biosynthetic gene clusters responsible for secondary metabolite production reveals unique characteristics distinguishing each strain from closely related Paraburkholderia species. On the basis of genotypic, phenotypic, chemotaxonomic and phylogenomic data, each strain should be classified as a novel species of the genus Paraburkholderia, for which the names Paraburkholderia translucens sp. nov. (=MMS20-SJTN17T=LMG 32366T=KCTC 82783T) and Paraburkholderia sejongensis sp. nov. (=MMS20-SJTR3T=LMG 32367T=KCTC 82784T) are proposed.

Two Gram-negative, aerobic, rod-shaped bacterial strains, 7MK25T and 6Y81T, were isolated from forest soil of Dinghushan Biosphere Reserve, Guangdong Province, PR China. Based on the results of 16S rRNA gene sequence analysis, strain 7MK25T showed the highest similarity (93.6 %) to Methyloferula stellata AR4T, followed by Bosea thiooxidans DSM 9653T (93.3 %). Strain 6Y81T had the highest similarity of 97.9 % to Lichenibacterium minor RmlP026T, followed by Lichenibacterium ramalinae RmlP001T (97.2 %). Phylogenomic analysis using the UBCG and PhyloPhlAn methods consistently showed that strain 7MK25T formed a sister clade to Boseaceae, while strain 6Y81T formed an independent clade within the genus Lichenibacterium, both in the order Hyphomicrobiales. The digital DNA–DNA hybridization and average nucleotide identity values between strains 7MK25T, 6Y81T and their close relatives were in the ranges of 19.1–29.9 % and 72.5–85.5 %, respectively. The major fatty acids of 7MK25T were summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c), C19 : 0 cyclo ω8c, C16 : 0 and C17 : 0 cyclo, while those of 6Y81T were summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c), C16 : 0 and C16 : 0 3-OH. Strains 7MK25T and 6Y81T took diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine as their dominant polar lipids, and Q-10 as their major respiratory quinone. On the basis of phenotypic and phylogenetic data, strain 7MK25T is proposed to represent a novel species of a novel genus with name Terrirubrum flagellatum gen. nov., sp. nov., within a novel family Terrirubraceae fam. nov., with 7MK25T (=KCTC 62738T=GDMCC 1.1452T) as its type strain. Strain 6Y81T represents a novel species in the genus Lichenibacterium, for which the name Lichenibacterium dinghuense sp. nov. (type strain 6Y81T=KACC 21 727T=GDMCC 1.2176T) is proposed. Rhodoblastaceae fam. nov. with Rhodoblastus as the type genus is also proposed to solve the non-monophylectic problem of the family Roseiarcaceae.

Three Gram-stain-negative, aerobic, non-motile and coccobacilli-shaped bacterial strains, designated as NPKOSM-4T, NPKOSM-8 and MO-31T, were isolated from rice paddy soil. They had 96.5–100 % 16S rRNA gene sequence similarity to each other, and strains NPKOSM-4T and NPKOSM-8 showed 100 % 16S rRNA gene sequence similarity, confirming that they were the same species. Comparative analysis of 16S rRNA genes with closely related type strains showed that three isolates were most closely related to Falsiroseomonas terricola EM0302T (96.1–97.8 %), Falsiroseomonas wooponensis WW53T (95.51–96.3 %) and Falsiroseomonas bella CQN31T (96.0–96.5 %), respectively. The genomes of strains NPKOSM-4T and MO-31T consisted of 4 632 875 and 6 455 771 bps, respectively, with 72.0 and 72.1 mol% G+C content. The average nucleotide identity (ANI), average amino acid identity (AAI) and digital DNA–DNA hybridization (dDDH) values between strains NPKOSM-4T and MO-31T and type strains of Falsiroseomonas species were lower than the cut-offs (≥95 % for ANI, ≥95–96 % for AAI and ≥ 70 % for dDDH) required to define a bacterial species. The major fatty acids of strains NPKOSM-4T, NPKOSM-8 and MO-31T were C18 : 1 ω7c and C18 : 1 2-OH (<10 %) and the predominant quinone was Q-10. The polar lipids of strain NPKOSM-4T were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, one unidentified aminophospholipid and three unidentified aminolipids. The polar lipid profiles of strain MO-31T contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, one unidentified aminolipid and three unidentified lipids. Based on their distinctive phenotypic, phylogenetic, and chemotaxonomic characteristics, strains NPKOSM-4T, NPKOSM-8 and MO-31T are considered to represent two novel species of the genus Falsiroseomonas, for which the names Falsiroseomonas oryziterrae sp. nov. [to accommodate strains NPKOSM-4T (= KACC 22135T=JCM 34745T), NPKOSM-8 (=KACC 22134=JCM 34746)] and Falsiroseomonas oryzae sp. nov. [to accommodate strain MO-31T (= KACC 22465T=JCM 35532T)] are proposed.

A Gram-stain-negative bacterium, designated LG-4T, was isolated from sediment of Qiantang River in Zhejiang Province, PR China. Cells were strictly aerobic, non-spore-forming, non-motile and short-rod-shaped (1.0–1.2 µm long and 0.7–0.8 µm wide). Growth occurred at 15–42 °C (optimum, 30 °C), at pH 5.0–9.0 (pH 7.0) and at 0–2.0 % (w/v) NaCl (optimum, 0.5 % NaCl). Strain LG-4T showed 95.75–96.90 % 16S rRNA gene sequence similarity to various type strains of the genera Tabrizicola, Pseudotabrizicola, Phaeovulum, Rhodobacter and Wagnerdoeblera of the family Paracoccaceae, and the most closely related strain was Tabrizicola soli ZQBWT (96.90 % similarity). The phylogenomic tree showed that strain LG-4T clustered in the family Paracoccaceae and was positioned outside of the clade composed of the genera Wagnerdoeblera and Falsigemmobacter. The average nucleotide identity and digital DNA–DNA hybridization values between strain LG-4T and the related type strains were in the range of 74.19–77.56 % and 16.70–25.80 %, respectively. The average amino acid identity (AAI) values between strain LG-4T and related type strains of the family Paracoccaceae were 60.94–69.73 %, which are below the genus boundary (70 %). The evolutionary distance (ED) values between LG-4T and the related genera of the family Paracoccaceae were 0.21–0.34, which are within the recommended standard (≥0.21–0.23) for defining a novel genus in the family Paracoccaceae. The predominant cellular fatty acids were C18 : 1 ω7c, C19 : 0 cyclo ω8c, C18 : 0 and C16 : 0, the isoprenoid quinone was Q-10, and the major polar lipids were phospholipid, phosphatidylglycerol, phosphatidylcholine, aminolipid and two unknown polar lipids. The genome size was 4.7 Mb with 68.6 mol% G+C content. On the basis of distinct phylogenetic relationships, low AAI values and high ED values, and differential phenotypic, physiological and biochemical characteristics, strain LG-4T represents a novel species of a new genus in the family Paracoccaceae, for which the name Ruixingdingia sedimenti gen. nov., sp. nov. is proposed. The type strain is LG-4T (=MCCC 1K08849T=KCTC 8136T)